The use of tufting machines to create tufted articles, for example carpeting, is well known. The known types of tufting machines typically include an elongate framework having a base section, and a head seated on the base. An aligned series of needles, each of which is supplied with a yarn, is reciprocably driven through a backing material passed through a tufting zone defined on the framework beneath the needles to produce the tufted articles. As known, the needles will be mounted on an elongate needle bar extending the width of the tufted article, i.e., in the widthwise direction of the tufting machine. The needle bar in turn is reciprocably driven by a series of spaced push rods which are supported for reciprocating motion on the head of the tufting machine. Each push rod will be provided with a push rod housing and seal assembly. A rotatably driven tufting machine main drive shaft is housed within the head and drives the push rods. The main drive shaft is exposed to a recirculating oil bath for the purposes of both cooling and lubricating the tufting machine main drive shaft, as well as the push rods.
As the tufted article is produced, the backing material is transversely passed through the tufting zone and beneath the needle bar such that for each stitch cycle a row of tufts is formed in the backing material. In order to sew the next successive row of tufts, the backing material is advanced with respect to, and in timed relationship with the reciprocation of, the needle bar. However, due to the high speed at which modem tufting machines operate, oftentimes the needles are engaged in the backing material as it begins to advance, which thus tends to pull the needle bar to which the needles are mounted, and in turn flex or oscillate the push rods, in the direction of the movement of the backing material travel through the tufting zone. This flexure of the needle bar and push rods is typically not enough to substantially damage the machine, however, it does result in increased wear of the known types of seal assemblies used in the push rod housing and seal assemblies supporting the individual push rods for reciprocation. As a result of this oscillation and/or wear of the seal assembly, the cooling oil contained within the head is allowed to be passed along the exterior surface of the push rod through the seal assembly, with the result that the cooling oil then splashes or drips onto the backing material as it passes through the tufting zone with the result that the tufted article will become stained with the oil, necessitating the scrapping of that portion of the now tufted article, all of which reduces machine and operating efficiencies, as well as leading to increased maintenance requirements for replacing the seal assemblies to prevent this type of oil leakage.
A known type of push rod housing and seal assembly is illustrated in FIG. 1. A push rod housing 5 is shown having a first end 6 and a spaced second end 7. The push rod housing is formed about an axis A, and has an elongate continuous throughbore 9 defined therein concentrically about the axis. In known fashion, a tubular bushing 10 is received within the bore, and a tubular top guide or bushing 11 is received in the bore at the top end 6 of the push rod housing, both of these bushings being provided for guiding, i.e. serving as bearing surfaces, for the circumferential surface of the push rod (not illustrated) which reciprocates therethrough. The housing is provided with an annular mounting flange 13 having a radially spaced series of openings 13' defined therein, such that a separate fastener 13" can be passed therethrough for fastening the push rod housing to the base portion (not illustrated) of the head (not illustrated) of the tufting machine (not illustrated), in known fashion. A seal gasket 14 is provided for sealing the mounting flange on the base portion of the head in the effort to prevent oil leakage therethrough.
Still referring to FIG. 1, a known type of seal assembly 15 is illustrated for use with push rod housing 5. The seal assembly includes an annular felt washer 17 through which the push rod is passed. The felt washer will be soaked with oil as the washer passes along the exterior surface of the push rod as the push rod reciprocates through the push rod housing, and serves to lubricate the push rod and to prevent the passage of oil and out of the housing and onto the backing material. The seal assembly is also provided with an annular seal gasket 18, an annular push rod wiper seal 19, and a bottom retainer plate 21 for being threadably fastened to the second end 7 of push rod housing 5. So constructed, therefore, seal gasket 14, felt washer 17, and seal gasket 18 are provided for "sealing" the push rod housing, and the push rod, on the head of the tufting machine to prevent the passage of oil therethrough and onto the backing material.
Of note, however, the known types of assemblies do not include any means for bearing, i. e. guiding or supporting, the push rod as it extends therethrough, particularly during its period of flexure during the tufting operation. As a result of this, therefore, the flexure or whip in the push rod tends to wear against the felt washer 17, as well as the push rod wiper seal 19 through a constant oscillating motion, such that not only do these two parts wear, but that oil is allowed to pass along the push rod by hydroplaning underneath or past the felt washer and wiper seal, such that it continues to extend downward along the push rod, and will then splash or drip onto the backing material during tufting operations.
Examples of the known type of tufting machine push rod housing and seal assemblies are shown in U.S. Pat. No. 3,633,523 to Card; U.S. Pat. No. 4,048,930 to Card; U.S. Pat. No. 4,366,761 to Card; U.S. Pat. No. 4,419,944 to Passons, et aL; and U.S. Pat. No. 5,499,588 to Card, et al. In each of these patents, the known type of push rod housing and seal assembly, described above, is used for supporting the push rod of the respective tufting machines for reciprocation, and for sealing the push rod and push rod housing on the head of the tufting machine in the effort to prevent the passage of cooling oil therethrough and onto the backing material as it advances through the tufting zone during the tufting of the article on the machine.
What is needed, therefore, but seemingly unavailable in the art is an improved tufting machine push rod housing gland seal assembly, as well as an improved gland seal assembly that can be used with currently known push rod housings, which will prevent the leakage of oil from the head of the tufting machine onto the backing material as it advances through the tufting zone. What is also needed is such an improved push rod housing gland seal assembly which will have a bearing surface for that portion of the length of the push rod extending therethrough to prevent the flexure or whip of the push rod from unduly wearing the seals of the assembly, for example the lip seals or wiper seals, which seal the push rod on the housing, such that lubricating oil from the head of the tufting machine is not allowed to pass therethrough and onto the backing material of the tufted article. Moreover, there is a need for such an improved push rod housing and gland seal assembly which can be easily fit, or retrofit to new or existing machines quickly and economically, and which will improve the operating efficiencies of tufting machines by reducing, if not eliminating, the leakage of oil from the head of the tufting machine onto the backing material.